Flask



FIG. 1 is a perspective view of a flask of the present invention;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a left view thereof; and,

FIG. 7 is a right view thereof.

CLAIM The ornamental design for a flask, as shown and described.